Patina is defined as a film that is formed naturally on metal by long exposure to the elements or artificially as by acids or oxidation and is valued aesthetically for its color. On copper or bronze a patina tends to be either or green or blue in color and on sterling silver gray or black.
When creating a piece of jewelry you should consider whether to patinate or oxidate before starting work on the piece. Soldering and pickling will remove most coloration, so create any color after you have finished all such work. If you will only be drilling the piece, then you may feel free to patina the work at the outset.
It is very important when preparing a piece for patination that it is cleaned properly for coloration. The metal should be free of all oils from your hands. Water should stand evenly on the surface and not bead up on it like raindrops on your car after it has been waxed. To get the metal thoroughly clean, you can anneal it, pickle it, and rinse it with water. Alternately, you can clean the metal with pumice paste or with a glass brush. Any excess solder should be filed and cleaned away.
Patinating Copper
Deep Red Patina
- Clean both sides of your metal under running water with wet-and-dry paper.
- Paste both sides with a flux paste – either borax flux, or a powder flux.
- Heat the copper on one side until it glows orange. Turn it over and heat the
other side to the same color. Then quench it in water and pickle for a few minutes.
- The copper should be a beautiful red-purple color. If it is not, simply repeat.
- Gently polish or lightly oil the copper with either jade oil or soft beeswax.
Blue Patina
- Fill a small saucer with household ammonia.
- Cover the copper salt.
- Dampen the salt with water or vinegar.
- Place the copper and the saucer with the ammonia with in an airtight container.
- Allow the copper to sit for several hours to several days. Remove when the desired coloration is reached.
Green-Blue Patina
- Fill a sealable plastic container with either sawdust or tobacco.
- Add enough of the following solution, one part vinegar to three parts household ammonia, to just dampen your sawdust.
- Clean your copper by annealing, pickling, and running under water. Let dry.
- Place the copper in the sawdust mixture and cover completely. Seal the container and leave for at least one hour to several days until the desire finish is reached.
Black Patina
- Take a piece of Liver of Sulfur, about the size of your finger nail, and dissolve it in a cup or more of warm water.
- Heat the piece of metal to be treated and then dip in the Liver of Sulfur solution.
- Rinse in water after each dip until you reach your final desired color.
- The piece may be sanded lightly and polished. Raised areas will show the original color of the metal, recessed areas will remained blackened.
- Be sure to wear gloves and protective clothing when working with Liver of Sulfur. The fumes are dangerous and it should be used with good ventilation and covered right after use. It must not be allowed to come in contact with acids as a toxic gas is then rapidly evolved.
Patinating Silver
While Liver of Sulfur is usually used to form a black or gray patina on silver, there are a number of intermediate interference colors formed, especially if a weak solution is used. These include yellow, reddish brown, purple and blue. Some people recommend adding a small amount of household ammonia to the solution claiming it intensifies the lovely blue-green-red-purple interference colors one gets when using a dilute solution and slow approach. These pretty colors are not very stable over time because they continue to react with sulfur in the air and darken. You can sometimes 'save' them by spraying a lacquer over them. They may be retained if the surface is properly sealed. Acrylic resin is the recommended sealer for durability and resistance to darkening in light. Some jeweler’s lacquers also work. Envirotex® works very well for this.
Using Liver of Sulfur on Silver
1. Take a piece of Liver of Sulfur, about the size of your finger nail, and dissolve it in a cup or more of warm water.
2. Heat the piece of metal to be treated and then dip in the Liver of Sulfur solution.
3. Rinse in water after each dip. While Liver of Sulfur is usually used to obtain gray and black colors on silver, there are a number of intermediate interference colors formed, especially if a weak solution is used. These include yellow, reddish brown, purple and blue. Some people recommend adding a small amount of household ammonia to the solution claiming it intensifies the lovely blue-green-red-purple interference colors one gets when using a dilute solution and slow approach. These pretty colors are not very stable over time because they continue to react with sulfur in the air and darken. You can sometimes 'save' them by spraying an appropriate lacquer over them. They may be retained if the surface is properly sealed. Acrylic resin is the recommended sealer for durability and resistance to darkening in light. Some jeweler’s lacquers also work. Envirotex® works very well for this.
4. The piece may be sanded lightly and polished. Raised areas will show the original color of the metal, recessed areas will remained blackened.
5. Be sure to wear gloves and protective clothing when working with Liver of Sulfur. The fumes are dangerous and it should be used with good ventilation and covered right after use. It must not be allowed to come in contact with acids as a toxic gas is then rapidly evolved.
Reference: The Jeweler's Directory of Decorative Finishes, From Enameling and Engraving to Inlay and Granulation By Jinks McGrath
Links:
For a Free Tutorial on Copper and Brass Patinas Go to JewelryLessons.com or use the following link:
http://www.jewelrylessons.com/jewel/node/6697
For a great article discussing the use of Liver of Sulfur:
